update package.json to reflect contrib at v0.2.0.
update package.json to reflect contrib at v0.2.0.

andreialecu/grunt-contrib-cssmin,fracmak/grunt-contrib-cssmin,bhamodi/grunt-contrib-cssmin,nqdy666/grunt-contrib-cssmin,gruntjs/grunt-contrib-cssmin,MoLow/grunt-contrib-cssmin